Internal combustion engines that operate in a split engine mode to achieve fuel economy have been previously developed but have yet to achieve wide commercial usage. Selected cylinders of the engine are deactivated during split engine operation so that no fuel is fed to them but rather is fed only to the other cylinders. Intake and exhaust valve deactivators are utilized to provide this control of the cylinder operation. A V-8 cylinder engine will normally have one or two of its cylinders on each bank rendered inoperative by valve deactivators during the split engine operation to provide four or six cylinder operation and will have all eight of its cylinders functioning during full engine operation. Likewise a V-6 cylinder engine will have one or two cylinders on one or both sides operating during split engine operation for two, three or four cylinder operation and all six cylinders will function during full engine operation.
Prior patents disclose engine valve deactivators having various constructions and which are positioned at various locations between the camshaft of the engine and the controlled valve of the engine. For example, U.S. Patent of Winkler, Jr. U.S. Pat. No. 2,745,391 discloses the use of a valve tappet construction and cooperating control mechanism for some of the engines cylinders which will render the valves for the cylinders and, consequently, the cylinders inoperable except during starting, acceleration and high power output. The particular construction disclosed therein includes a hollow reciprocable cylinder, a piston in the cylinder forming an enclosed chamber therein, a fluid inlet passage for a chamber, a fluid outlet passage for the chamber in the piston, a control valve in the outlet passage, a spring urging the valve toward the closed position and a lever for opening the valve.
The U.S. Patent of Fuller, Jr. et al U.S. Pat. No. 4,050,435 discloses a cut-out device selectively operable to function as a rigid extension of a valve pushrod or as a deactivating means between the pushrod and its respective valve. An inner hollow piston is slidable within an outer cylinder and between a pair of axially aligned fluid isolated chambers. The piston is disposed in one of the chambers and a pushrod end is slidably received in the opposite chamber. Fluid pressure lines are connected to fluid ports in the outer cylinder such that the fluid ports are in communication with the chambers of the hollow piston.
The U.S. Patent of Jordan U.S. Pat. No. 4,175,534 discloses a valve deactivator which includes a rotatable first cylindrical member axially fixed on an elongated engine support and also includes a second cylindrical member defining an enclosed cavity with the first member while positioned on the support between the engine and the first member. A helical spring of the deactivator circles the cylindrical members thereof and has a first end axially fixed relative to the support and the second end that biases a rocker arm bearing toward the engine. Ports in the support and the first cylindrical member define inlet and exhaust passages to the cavity with the first cylindrical member in first and second rotational positions so as to allow the supply and exhaustion of pumped engine oil in the cavity in order to position the second cylindrical member axially along the support so as to control valve operation.
Other valve deactivators of the type to which this invention relates are disclosed by the U.S. Patent of Brown, U.S. Pat. No. 3,964,455, Cartledge U.S. Pat. No. 3,809,033, Benson et al U.S. Pat. No. 4,133,332 and Jordan U.S. Pat. No. 4,114,588.